1. Field of the Invention
The present invention relates generally to a device and method for delivering an aerosol drug. More specifically, the invention is an improved device and method for delivering an aerosol drug to a patient in a more effective and convenient manner.
2. Description of the Related Art
Therapeutic drugs are most commonly delivered to a patient via an oral dosage, such as a pill, capsule or tablet, or via an intravenous solution. Oral dosage forms of drug delivery require a longer time before the effects of the drug are realized by the patient. In addition, drugs delivered to a patient in oral dosage form suffer from a loss of therapeutic effect due to hepatic metabolism. Intravenous drug delivery can be painful and is generally inconvenient for patients not resident in a health care facility. Inhalation drug delivery overcomes the disadvantages of both oral dosage delivery and intravenous drug delivery, but has yet to gain wide acceptance and use. One possible reason for the limited role of inhalation drug delivery, despite its increased efficacy and convenience, is the lack of a suitable device and method for simple, reliable and repeatable delivery of the drug in an aerosol form to the patient. Existing devices for delivering an aerosol drug are suitable for use with only a limited class of therapeutic agents, such as drugs for the treatment of asthma, or are not sufficiently portable, repeatable, reliable or simple to use.
Accordingly, a device for delivering an aerosol drug is needed that is both effective and convenient to use. Such as a device must be capable of delivering a wide range of drugs to a patient in the form of an aerosol in a portable, repeatable, reliable and simple manner. As used herein, the term “aerosol” is intended to include vapors, gases, fine particles, and the like, both visible and invisible, generated by a heat source acting upon an aerosol forming means in a manner according to the invention as described herein. As so defined, the term “aerosol” specifically includes any pharmacologically or physiologically active agents, and any desired additives, such as an aerosol forming agent, irrespective of whether they produce a visible aerosol. As used herein, the term “in heat conducting relation” is intended to mean a physical arrangement of two or more components whereby heat is transferred by conduction or convection from a heat generating source (e.g., heating element) to a thermally conductive component (e.g., heat conductor and/or substrate) substantially throughout the heat generating period of the heat source. A heat conducting relation can be achieved by locating the components in direct physical contact or in close proximity to one another while the heat source operates to generate heat.